Posts by Chris Cox

Con?

Sure.. I'll dispute a bit.

You're taking a pro iSCSI stand. That's pretty obvious.

FCoE is a natural extension of FC. Unlike iSCSI. So, iSCSI is a competing technology, it is not a migration or upgrade technology. So while it's nice to SAY that FCoE is a "con" if you have a bias torwards iSCSI (which is something else entirely), the fact is that FCoE, is a better path for FC users should they choose to migrate away from fibre and use a converged network in the future.

10Gb iSCSI... now that's somewhat of a con job isn't it? Do you even get full gigabit potential out of today's iSCSI? Sure, you can do aggregation, and talk in terms of multiple hosts and such to prove that iSCSI works today. But AFAIK, iSCSI is pretty poor today host to SAN, and I don't expect to see 10Gb performance when folks move to 10Gb either. And, while we're on the topic of 10Gb, you do understand the run length limitations of 10Gb copper right? All I'm saying is that there could be a fairly large number of folks that will find 10Gb to be expensive to deploy because it means moving to fibre just because of the 14M run lengths of copper CX4's.

My current SAN units SATURATE a 4Gb line... that's a SINGLE host talking to the SAN. Good SAN arrays can easily take full advantage of 4Gb and 8Gb today... something that iSCSI simply doesn't allow even at the lowly 1Gb speeds. Is that worth something? I think so. You can knock fibre channel tody because of its cost... certainly true. You do pay for the ability to get full performance (with or without aggregation). If 100MB/sec floats your boat, and you don't need more than that, I say iSCSI is going to work fine for you. If you need 400MB/sec+, then I KNOW, you'll be better off with FC.

Do you know how much 10Gb ethernet ports cost? 10Gb ethernet network cards? Sure, it's early on... but at least today, if 1Gb is a joke, and you believe 10Gb to be better than FC, I think you'll find that 10Gb iSCSI likely performs comparably to 4Gb fibre... and I think you'll find the cost to favor FC in that case. And... if you HAVE to move to 10Gb fibre ANYHOW, well.. clearly FC holds the advantage in that case.

There are other considerations though. The ability to route iSCSI can be a very interesting thing. So that also needs to be kept in mind. However, SANs, whether iSCSI or FC, are fragile. Not sure if adding routing to the picture is necessarily a wise idea.

Missed point?

My point is that with Red Hat you get an "enterprise" moving target, picking up technologies and dropping them (on top of the customer's head). You'll just have to trust me, customers don't like vendors that change their mind every 3 seconds. I mean, Red Hat went OUT OF THEIR way to sell the world on "superior" virtualization of their flagship enterprise RHEL 5... and some bought it hook, line and sinker.

As far as the merits of KVM, you and I are in agreement, I did mention that kvm is the future for virtualization... or is it?? I think we need to ask Red Hat that question a year from now... they'll probably want everyone to switch to something else... again...

Uh... virtualization history rewrite by Red Hat

Just like they did with RHAS 2.1 (remember how Red Hat said that they didn't have an enterprise Linux release until RHAS 3?), now we have Red Hat abandoning Xen which they included in their last enterprise distribution. It was included to show the world Red Hat's commitment to virtualization and how, since they waited until Xen was stable, they were better situated to compete against Novell's SUSE.

Well... sounds like Red Hat didn't like what they were seeing from their own developers and decided to do ANOTHER history rewrite... sigh...

When Novell SLES 10 came out with Xen (prior to RHEL 5), Red Hat claimed it was junk and that NOBODY should use it.

Then with RHEL 5, Red Hat declared Xen was truly enterprise ready and pushed their edition of Xen (yes... Red Hat went from Xen is junk to Xen is #1 in just a few months).

See:

http://www.redhat.com/rhel/server/advanced/virt.html (Xen)

And now? Bye, bye Xen... we meant KVM?? Oh really.... Red Hat needs to learn that switching horses all of the time causes grief for their customers. With that said, I think KVM is likely the Linux developed FOSS virtualization of choice for the future. But who knows what Red Hat will say next year...

Historical Aside: With regards to the elusive RHAS 2.1, I have a client I work for who pays for Red Hat support, every time they call in they would say... "upgrade to v3".... sheesh... Remember, Red Hat has publicly stated that RHAS 3 was their FIRST enterprise version (sigh). Sorry customer, you must have made a mistake.

... and on and on. Red Hat tends to say something new and different everytime you talk to them :)